How to get a green laser module?
It is a typical special laser light source in type of doubled YAGs. 532nm green DPSS laser is originally obtained via infrared laser diode at about 808nm or 980nm wavelength. After pumps a small slab of glass or yttrium aluminum garnet (YAG), doped into neodyminum, to produce a 1.06 micron laser beam, sent into a lithium niobate crystal at a certain angle to cause a nonlinear optical process, and converted to a green photon via two infrared photons at wavelength of 532nm.
532nm DPSS laser made green laser module gets quite low laser beam divergence of less than 1mrad and special TEMm00 laser beam mode. Being made into dot, line or cross line laser device, it just enables the most sensitive color, the most easily absorbed, and the most visible green laser light source projection, and the most compact size laser light source for different need. It fulfills the tasks where the highest level of accuracy laser alignment in high tech and formal industrial use.

How to get a red laser module?
Red diode laser gets different materials(P-N) at a junction. A direct band-gap laser for red is typically made via Gallium-Indium-Phosphide or Aluminum-Gallium-Indium-Phosphide. AlGaInP diodes will have better mode structure, tighter beams, and are in laser pointers, these range of 635 nm to 650 nm (red). Formerly, Gallium Arsenide was used for red with multi-mode.
Typically, a red laser module gets formal wavelength of 635nm, 650nm and 666nm. Red laser diode gets the longest developing history and the matures laser tech. The finished production also gets intense and powerful red laser light emission via a red laser diode, assuring the most reliable performance and the lowest production cost owing to its mass production and wide applications.
Being made into a direct diode emission device of dot, line, cross line laser module, it is not as bright as a 532nm green DPSS laser system, however, it is just an excellent presentation tool for all moderate accuracy positioning works.

What is the different between a green laser and a red laser?
There is no exact decision on which type of laser is better, just depends on what your criteria for goodness is. Below are just some of features of each laser:
Direct diode made red laser module gets even more simple structure and components. It gets even more stable performance in long lasting use, and more competitive price.
Red laser is not too bright, thus it is only applicable for formal presentation, indication, close distance and formal lighting occasion used laser alignment works.
532nm green laser obtains the most visible and the brightest green laser light emission because human eyes are the most sensitive to green light, thus it appears brighter laser light than red laser with the same output power.
Green laser module is usually applied for high level of accuracy and precision dot, line, cross laser alignment works. It provides ideal laser light source for industrial precise device manufacturing works, high tech, lab experiment, laser medical therapy and astronomy research works etc.